An airbag is typically inflated with a pressurized source of gas. While airbags originally included single stage inflators, or inflators that would supply a constant effective flow area for a variable pressure, some recent airbag inflators have been adapted to supply more than one flow rate to inflate the airbag. These ‘dual stage’ airbag inflators typically are initiated by a control logic that determines what ‘type’ of crash event is being experienced and provides a selected flow rate to inflate the airbag. However, these dual stage inflators typically provide only adaptive vents, adaptive columns, dual-stage pyro inflators, or other systems that provide limited utility. Hybrid pyro inflators may also be used, but are sensitive to pressure waves within the system that affect the burn and subsequent development of gas flow and pressure.
With continual development in understanding crash dynamics and what parameters would be useful in altering inflation mass flow rates and to what degree, dual stage airbag inflators may no longer provide a desired flow rate for a specific initiating event that can be somewhat accurately detected and compensated for in an airbag inflation sequence. What is needed, therefore, is an apparatus and method for inflating an airbag that may be tailored to a specific defined initiation event. A favorable apparatus would be readily altered for use in different vehicle types, such as small cars, medium duty trucks, and light duty trucks.